The present invention relates to a method and system for casing air dried tobacco, and more particularly to an apparatus and method for conveying air dried tobacco through a relative humidity controlled structure for bringing the tobacco in case in a controlled environment.
One form of commercially grown tobacco is commonly known as air dried tobacco. Air dried tobacco is cured or dried generally by hanging the tobacco (tobacco stalks) in curing sheds or structures. Burley tobacco is a common example of such air dried tobacco.
Burley tobacco plants grow as relatively tall stalks with the tobacco leaves growing radially out from the stalks. Typically, when the burley tobacco stalks are cut, the widest portion (bottom of the stalk) of the main stem is manually skewered onto a stake or rod. Generally, the rods are about five or six feet long and about five or six different stalks are threaded onto each stake. After the threading process, the stakes are transported to a curing shed or barn for curing or drying the tobacco. A portable curing cell for drying or curing this type of tobacco is described in my co-pending U.S. application Ser. No. 850,410.
Once the tobacco is properly cured or dried, it must be brought in case for further processing for market. The dried tobacco cannot be adequately handled otherwise since the dried leaves are quite fragile and brittle and tend to break apart at the slightest touch. Casing tobacco requires that the cured tobacco be brought to a predetermined relative moisture content, preferably at least 14 percent moisture content for processing for market. Various ways are known to case the tobacco but, these ways are inadequate for a generally high volume continuous harvesting and processing system.
For example, in the case of cured burley tobacco, one method of casing tobacco involves essentially laying the tobacco stalks in a pile, spraying water onto the stalks and subsequently covering the pile with tarpaulins. This method has proved problematic in that it is generally impossible to obtain a uniform relative humidity content within the tobacco throughout the pile. In other words, the leaves sprayed with water tend to be overly soaked while the inner leaves tends to remain dry. Also, the tarp tends to retain excessive heat and the tobacco which has not been adequately sprayed will dry out excessively under the tarp instead of being brought to a proper humidity condition.
Additionally, tobacco farmers harvesting air dried tobacco tend to be at the mercy of the elements as far as casing the tobacco is concerned. Typically, the farmers will pull the cured tobacco from the curing sheds early in the morning when the conditions are relatively humid. Foggy mornings are the optimum condition. If the conditions are proper, the tobacco will have an adequate degree of moisture content so that the workers can handle the tobacco for processing. However, once the relative humidity in the air decreases as the day heats up, the farmers can no longer process the cured tobacco and must wait for the next morning or otherwise adequate weather conditions.
Thus, what is needed is a system and method for continuously casing tobacco so that the modern tobacco farmer can operate and sustain a relatively large volume and continuous harvesting and processing system.
Controlled growing environments for plants are known, but do not address the needs of the air dried tobacco farmer. For example, U.S. Pat. No. 4,068,405 discloses an apparatus and method for establishing and maintaining a controlled environment for the growth of food yielding plants and includes a number of multiple layer continuous chain drive systems each supporting an array of plant trays. U.S. Pat. No. 4,064,648 discloses a greenhouse insulating system for reducing heat loss from the structure. Systems are also know for conditioning cut tobacco, such as U.S. Pat. No. 2,777,446 which discloses a system and apparatus for cooling and bulking cut tobacco. This system, however, pertains to bulking and processing a type tobacco which has already been cut, dried, and brought to a predetermined relative moisture content. This method pertains to flue dried tobacco, which is harvested in leaves, and does not address the problems faced by the air dried tobacco farmers, particularly the burley tobacco farmers. U.S. Pat. No. 5,050,318 discloses a dryer racking system for drying produce in a barn and includes an endless conveyor to which are attached a plurality of containment devices which can be packed with produce such as tobacco leaves. This system also does not address the problems of adequately curing air dried or cured tobacco.